Can unconscious brains think? Coma, philosophy of mind, and the media.

By
Michael
Published: February 5, 2010Posted in: Health, good journalism, philosophy
Can unconscious brains think? Coma, philosophy of mind, and the media.

“Ok brain. I don’t like you and you don’t like me. Let’s just do this and I can go back to killing you with beer.”  - Homer Simpson

A new piece of research has elicited headlines around the world in today’s newspapers such as “Coma patient ‘talks’ with his thoughts” and “Coma victim talks via brain scanner“. These articles tell us that researchers have “unlocked” some coma patients’ minds and have proven that they are conscious but unable to move or communicate in normal ways.

It’s a terrifying idea.

But outside of the mainstream media, some scientists and other researchers are sceptical of these sensational claims. Ken Weiss, professor anthropology and genetics and Penn State University, argues on his group blog “The Mermaid’s Tale” that we should be cautious of attributing “consciousness” to these patients since unconscious parts of brains can respond to stimulus.

Many experiments on humans who have had surgery that impaired one of their hemispheres, or separated their two hemispheres, have shown that rational, responsive, decision-making capability exists independent of consciousness. Other recent work shows that conscious awareness may monitor, but comes split seconds after decisions are made by the brain. In other words, brains can think without being conscious.

Obviously, such claims depend on what we mean by “consciousness”. For example, if you think consciousness is the ability to demonstrate “rational, responsive, decision-making capability” then it makes no sense to claim that unconscious brains can do that. Such a brain is, by definition, conscious.

But presumably we mean something a little more by “consciousness”. Presumably we require some degree of “self-reflection” for something to count as conscious — some degree of awareness of the self.

So, are the patients in the new study conscious? To answer this, we don’t need to get bogged down in confusing (and confused) philosophical discussions about what consciousness is. This is obviously the case if you consider more everyday examples: I don’t need to know what consciousness is to decide whether or not you are conscious. I decide that just by talking to you. In a sense, we’re all experts at making such decisions.

Similarly, we should be able to decide whether or not (or to what degree) the coma patients are conscious without getting bogged down in definitional questions. If these patients can express desires and beliefs then there can be little doubt that they are conscious.

Ken asks his readers the following question:

For example, suppose it could be shown that these unfortunate people are not conscious, but that their unconscious brains are functioning. Should we ask those partially aware brains if they want to live or die?

If these patients are functioning to such a degree that we can ask them whether they have a desire to live or to die, then it makes little sense to conclude that they are still unconscious. The fact that they have their eyes closed and cannot move does not change matters: if they can behave as though they are conscious, then they are.

The idea that we could “talk” to a patient’s mind, but not to them is a rather ridiculous idea. The sillyness of the idea is what makes the above quote by Homer Simpson funny – you can’t talk to your mind because you are your mind!

In the particular study in question, there can be little doubt that the patients (particularly one of them) who have been diagnosed as being in Vegetative State have some significant degree of consciousness. One of these patients could understand a task described to them, and answer several questions about his life correctly. As Vaughan at Mindhacks said,

Out of these six simple questions, the patient ‘responded’ correctly to 5, suggesting that they were genuinely understanding, considering and making a conscious response. This was in a patient who had no external signs of consciousness. (My italics.)

ResearchBlogging.org

Monti MM, Vanhaudenhuyse A, Coleman MR, Boly M, Pickard JD, Tshibanda L, Owen AM, & Laureys S (2010). Willful Modulation of Brain Activity in Disorders of Consciousness. The New England journal of medicine PMID: 20130250

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Fish oil: Bogus or not?

By
Michael
Published: February 3, 2010Posted in: Bad Science, Health
Fish oil: Bogus or not?

In a previous post which considered some of the bogus science claims made by the Australian TV show Today Tonight, I had a brief look at a few things that fish oil is supposed to treat. It seemed fair to say that counter to the strong claims made by TT, the evidence suggests that fish oil is not a good way to treat arthritis nor arrythmia. I also said that it didn’t seem to be a good treatment for depression.

A reader pointed out to me that in fact there was some evidence that Omega-3 fatty acids helped with depression. A number of reviews of the literature on the efficacy of fish oil on mood disorders (like this one, this one and this one) suggest that fish oil might help with depression. But, as each of the reviews point out, many of the studies are small and contain methodological problems. Almost all the reviews conclude that more research is needed to say anything conclusive about the efficacy of fish oil as a treatment for mood disorders.

Today, the ABC and Sydney Morning Herald carried stories about another study purporting to show that fish oil was a good treatment for mental illness. This time the claim is that when administered to children, it prevents the later onset of psychosis or schizophrenia. And while this study’s conclusions are very enthusiastic, it is very small with only 81 participants.

What should we conclude about all this?

The overwhelming conclusion is the boring old line: “more research is needed”. But we also know that there is mounting doubt about the efficacy of anti-depressants over placebos. It is increasingly looking like most of the reason why anti-depressants work is the hope that they provide patients. Moreover, unlike fish oil, antidepressants have significant adverse side-effects. So, given that fish-oil might chemically help with mood disorders, that it can provide hope (which is proven to help with depression) and that it has no significant side-effects, it seems like something that’s worth a try and certainly worth more research.

[Here's a link to a fascinating article in Newsweek about the dwindling evidence supporting the use of anti-depressants.]

[Here's the results of a search of PubMed for "omega-3" and "depression". Lots of studies, nothing very conclusive.]

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Actually, maybe economists did prove money can buy happiness…

By
Michael
Published: January 22, 2010Posted in: Health, good journalism, philosophy
Actually, maybe economists did prove money can buy happiness…

A little while ago, I wrote a post about an article in Science about the relationship between “objective” measurements of “quality of life” and subjective measurements of “life-satisfaction”. The article found a very high correlation between these measurements leading the authors to claim that there was now “objective verification” of the subjective measurements often used in research.

As I pointed out in the previous post, lying just behind the claim of verification was the claim that money can buy you happiness. If quality of life and life satisfaction are highly correlated, then perhaps since quality of life can be bought, so too can life-satisfaction.

At the time I pointed out that there were some problems with the research. I also wrote a letter to Science which I have just been informed they are not publishing. I did, however, get a thoughtful response from the authors who redid some of their calculations to take account of my criticisms. I’m copying below the letter and the authors’ reply for your interest.

Here’s my original letter to Science.

In their report “Objective Confirmation of Subjective Measures of Human Well-being: Evidence from the U.SA.”, (17 December) A. Oswald and S. Wu compared subjective life-satisfaction data of geographical areas across the United States with objective measurements of quality of life in those areas. Since they found a significant correlation between the two measurements, they conclude that subjective life-satisfaction data “contain genuine information about the quality of human lives.”

It is widely known that life-satisfaction judgments are subject to arbitrary contextual factors (1 – 3) and focusing illusions (4). It is therefore crucial that life-satisfaction data are collected in such a way that contextual priming of subjects is either avoided or controlled for.

The life-satisfaction data used by Oswald and Wu come from a the United States Behavioral Risk Factor Surveillance System (BRFSS) – a survey that collects data mostly about personal health. After roughly 100 questions, the survey asks for a life-satisfaction judgment.

Although Oswald and Wu make no mention of the  nature of the other questions asked in the survey, their regression analysis does control for socioeconomic factors. They do not, however, control for health factors which make up the majority of the questions asked of the respondent prior to the life-satisfaction question.

Given the literature on the context-dependence of life-satisfaction judgments and the focus of the survey on the respondents’ health, it is to be expected that the their judgments of life-satisfaction would be strongly correlated with their responses about the status of their health. The life-satisfaction judgments are therefore better interpreted as judgments of satisfaction with personal health outcomes.

Thus, Oswald and Wu’s conclusion that subjective judgments of life-satisfaction are strongly correlated objective measurements of quality of life is not warranted. Rather, given the contextual priming of the respondents, the conclusion should be that subjective judgments of personal health satisfaction are strongly correlated with objective measurements of quality of life.

This alternative conclusion, although not uninteresting, is not as surprising as the conclusion drawn by Oswald and Wu.

1. N. Schwarz, F. Strack, European Review of Social Psychology 2, 31-50, (1991)
2. N. Schwarz, F. Strack, H. P. Mai, Public Opinion Quaterly 55(1), 3-23, (1991)
3. S. Oishi, U. Schimmack, S. Colcombe, Journal of Experimental Social Psychology, 39(3), 232-247, (2003)
4. D. A. Schkade, D. Kahneman, Psychological Science 9(5), (1998)

Here’s the authors’ reply.

Response to Slezak’s letter

Andrew Oswald and Steve Wu

We are grateful to the author for his letter. Michael Slezak makes a valuable, interesting point. He is concerned about ‘priming’, namely, about the possibility that people’s life-satisfaction answers are influenced by the exact questions they answered before they reached the life-satisfaction question. He would like us to control for people’s health. It should be said that it is intrinsically unlikely that to do so would affect the nature of any cross-state correlation; this is because Americans in each state answer the same questions before they respond to the life-satisfaction question; hence, put loosely, any ‘bias’ is likely to wash out across states.

But to check this, we have re-done our calculations in the way Slezak suggests. We get the same answer as before.

We re-ran the life-satisfaction regression equation including now (i) an extra independent variable for general health on a self-reported 1-5 scale, as well (ii) one for the number of days in the last 30 days where physical health was not good. Both health-measure variables are statistically significant, as would be expected. However, the two sets of state-dummy coefficients (with and without the health controls) turn out to have a high correlation coefficient of 0.93. Moreover, the new state coefficients with health controls continue to be strongly correlated with the Gabriel state ranking: r = -0.53 (vs. -0.6 that we got originally).

Thus our article’s finding — there is a match between objective and subjective well-being — is unaffected. Nevertheless, we are grateful to Michael Slezak for suggesting this check.

Andrew J Oswald

Professor of Economics

University of Warwick UK

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How risky is a home birth? Some thoughts about the number crunching.

By
Michael
Published: January 20, 2010Posted in: Health, good journalism
How risky is a home birth? Some thoughts about the number crunching.

For some time now, there has been a heated debate in Australia about home births. Home birth advocates argue that a woman should have the right to choose how to give birth to her baby and if she chooses to have a home birth, that choice should be supported by providing the her with adequate care. Others claim that providing that kind of care encourages home births which are inherently dangerous.

Part of the problem with the debate is that it is sometimes dominated by crazies on both sides. On one side, some have called for the unnecessarily oppressive act of banning home births while on the other side, you see a lot of hippy-talk about the “sacred” and “natural” act of giving birth (see hilarious videos below).

Amid all this rhetoric, it was refreshing to read health reporter Melissa Sweet analyse the numbers of the relative risks of home versus hospital births as reported in a recent study published in the MJA. She points out that newspaper headlines reporting that “Babies are seven times more likely to die during home births” are exaggerating the degree of confidence the researchers have in the numbers.

The take-home message of Sweet’s article is that “there is quite a lot of good news for home-birth advocates in this study.” But reading her own interpretation of the figures, I don’t think this is so clear. She writes:

Where the media generally reported home-birth babies being seven times more likely to die during delivery, the estimate ranges from them being anywhere between 1.5 and 36 times more likely to have this happen.

So even the most generous interpretation of the results mean that if you choose to have a home birth, you are imposing a 50% increased risk of death on your child but as Sweet points out, it could be much worse.

Sweet continues:

A similar caution surrounds the widely reported finding that home-birth babies were 27 times more likely to die from lack of oxygen during delivery. Again, this finding had wide confidence intervals, with the estimate ranging from eight to 89 times greater — clearly, another one to take with caution.

Again, at the most generous interpretation, babies being eight times more likely to die from lack of oxygen seems like a very serious risk to impose on the child.

Certainly, as Sweet says, it is the right of mothers to choose how and where to give birth to their children but these significant risks ought to be communicated very clearly to parents. It seems to me the benefits of home birth are far outweighed by the apparent risks.
ResearchBlogging.org

Kennare RM, Keirse MJ, Tucker GR, & Chan AC (2010). Planned home and hospital births in South Australia, 1991-2006: differences in outcomes. The Medical journal of Australia, 192 (2), 76-80 PMID: 20078406


Here’s some examples of the crazy end of the pro-home birth side.

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